Buttonhole-sewing-machine attachment.



B. Mi-K ELL I BUTTONHOLE SEWING MAUHINB ATTACHMENT.

APPLICATION IILED'DEO. 20; 1912. I

Patented June 30,1914.

onus-an sear orator.

- BERNARD IVE. KRELL, OF NEW YORK N. Y.

BUTTONHOLE-SERNING-MACHINE ATTACHMENT.

Specification of Letters Patent.

Application filed December 20, 1912. Serial No. 737,771.

ter of the machine is locked against operation to pierce the fabric.

A further object of the invention is to provide such an attachment that can be readily applied to the conventional form of button hole sewing machines of the well.

known Singer type.

A. further object is to provide an adjust ment to vary the position of the thread, and also to vary the tension of the operating 1 member for the device.

In. the accompanyingflrawing, showing one embodiment of my invention, Figure 1 shows portions of a button hole sewing machine of the Singer type, and Fig. 2 is a perspective view of the device detached and enlargedl Fig. 3 is a plan of the cam-andlever timing device ordinarily used to time the cuts in'buttonhole sewing machines.

In the machine shown in Fig. 1 is the usual main driving wheel 2 that through suitable connections operates a needle bar 3,

and a cutter bar 4-, carrying respectively a needle 5 and a cutter 6 that will pierce the fabric to form the button hole. The thread 7 coming from a spool or other source, passes through a number of guides 8, 9, 10 and 11, and thence through suitable other guides, not shown,-to the needle 5. The connections for actuating the cutter 6 and cutter bar 4: are shown as comprising a spring pressed controlling member 16, a n'nain operating lever 17, a link 18 connected to the lever/17 and having at its upper end a slot 19, and a lever 20. The latter lever carries a pin 23 riding in the slot 19. A rock arm 21 pivoted on the link 18 near the lower end of the link, is provided witha shoulder, 22

adapted to engage the under face of the pin 23, by which means the lever 20 and the rock arm 21 are copnected for positive movement. the drawing, the shoulder 22 is away from the pin 23 and upon the link 18 being elevated by the lever 17 thepin 23 will ride But in the position shown in free in the slot 19 and the lever 20 will not be oscillated. It is understood that this lever 20, when swung, will depress the cuttor (3, forcing it through the fabric. The rock arm 21 can be swung by a'spring 24 to bring the shoulder 22 under the pin 23, but

is normally held in its inoperative position,

as illustrated,by the engagement of its arm 29, formed upon it, with one arm of a suitably pivoted bell-crank 25, normally engag ing and positioned by spring-actuated contact of its other end with the cylindrical barrel of a releasing cam 26, provided with asuitable activelimb, and mounted on a timing shaft 27, operably connected with the driving mechanism of the buttonhole machine; in

iatented June 3t), 1214.

the normal operation of which the cam 26,

once during each of its revolutions, retracts the bell-crank 25, withdraws its free end from and releases the arm 29, permitting spring 24; to swing the arm 21 to bring shoulder 22 under the pin 23, and thereupon the swinging of lever 17 will cause the depression of the cutter 6.

The parts described so far are well-known in this art and form no part of the present invention. But it will be understood that any meansthat will lock the lever 21 in the position shown, will preventswinging of the arm 20 when the lever 17 is swung, and hence absolutely prevent the operation of the cutter when the mi 29 is released by the said cam.

The present invention provides a swinging lever 30 having at one end a hook 31 that, when the lever is swung, will engage a. pin 32 on the lever 21., and thereby prevent the shoulder 22 from passing under the pin 23, whereby it is impossible to cause the operation of the lever 20 and the advancing of the cutter 6. The other end of the lever 30 is provided with a suitable eye through which the thread 7 is passed, and which thread is held under tension by the tension devices common in this art. The lever is shown as pivoted so that the'eye 33 engages the thread between the tension members 11 and 12, but deflects the thread out of the direct path between these members, whereby considerable pull is exerted on this arm of the lever 30. llt will be observed from Fig. 1 that the thread thereby holds said lever with its hook 31 disconnected from the pin 32, permitting free movement of the lever 21 by its spring when arm 29 is released by the bell crank 25-. Furthermore, the {eye 33 released by the bell crank.

is shown as a portion of a slidable plate 34 that is slotted for the reception of adjusting screws 35 and 36, permittingthe eye member to be moved toward and from the axis of the lever for adjustment.

The lever 30 is pivotally mounted on the sewing machine arm and adjustably relatively thereto and to the'members and thread with which it (to-acts, being pivoted on a slotted plate 38 which is clamped in adjusted position against said arm by a screw 42, which engages a slot 41 in said plate and a tapped hole in said arm. its shown, a coil spring 37 connects one arm. of the lever 30 with a supporting plate 38, the latter having a series of holes 39 at which one end of the spring is hooked, and the lever being shown as having a series of holes 40 in which the other end of the spring is hooked. By changing the spring to different holes in the lever and support, a number of different tensions can be'provided for the lever, as suit" able for its proper operation. It will be seen that the plate 33 can be adjusted on the screw 42 and clamped in any desired position, whereby the hook end 31 will properly engage with the screw 32 on the lever 21. in order to limit the swinging of the lever by the thread, Lprovide a stop pin 45 on the carrierplate 38, that will be engaged by the lever, as shown; I

In the operation of the device the lever is adjusted to engage the thread between the tension members, sothat the hook will be held away from the-pin 32, and the spring 37 put under tension. When the thread breaks the spring will swing the lever to the position indicatedin broken lines in Fig. 1. that will bring the book 31 to engage the pin 32. This will absolutely prevent swinging of the lever 21 by the spring 24 when the arm 29 is Consequently, the shoulder 22 cannot be brought under the pin 23, and therefore the lever 20 will not be actuated by the lever 4-7, and the knife or cutter 6 will not be caused to pierce the fabric.

Sewing machines are commonly run so fast that apparatus, such as is comprised in my invention, in order to operate in proper time relations with the sewing machine members, must be made practically instantaneous in operation, which is best accom" plished by spring-actuation of the main lever 30. Other devices for accomplishin the same objects have embodied levers engaged by the force ofgravity, and have proved unsatisfactory in operation because a motion' due to gravity alone requires too long a time to become accelerated to the requisite speed, As illustrated in Fig. 1 the pull of the thread 7 on the lever 30 is about four-fifths of the normal tension in the thread. The side plate 34, in which the thread eye 33 is formed, can be advanced toincreased by retracting said slide. Further,

the pull can be varied by adjusting the position of the plate 38, by which means the mounting axis of the lever 30 can be fad justed in a circle struck from the center of.

the engaging pin 32 on the roclearm 21, or' somewhat out of said circle if the hook 31 be altered in form, by filing it out, or otherwise. Adjusting the location of said axis raises the eye 33 toward the tension member 11 or depresses it toward the tension device 12,-of the sewing machine. The former increases and the latter decreases the length of the true arm of the lever 30 relatively to its fulcrum and the thread, and correspondingly vary the efi'ect, on said lever, of an unvarying thread-tension. I am enabled, by these location adjustments and by adjusting the spring 37, as aforesaid, to adjust my step to function satisfactorily in co-action with any sewing thread, however fine, without subjecting it to a dangerous tension; and to accomplish this largely by location adjustments which change the direction of the re sultant of a uniform thread-tension acting in the two lines in which the thread diverges from the eye 33. Prior apparatus for this purpose had no such location adjustment and no spring and necessarily no spring-adjustment, or an equivalent for it, and hence their range of duty was very narrow.

Having thus described my invention, I claim 1. An automatic cutter-stop for buttonhole sewing and cutting machines comprising a member adapted to engage and inopcrativcly position a cuttri oprraiing moon her of such a machine, to engage a sewing thread operative in such a machine, and to be retracted by tension in such thread. anda l spring operativcly connected with said member and adapted to be strained by such tension. and by its recoil, when such tension is diminished, to cause said first named member to move to its engagement position.

2. An automatic cutter-stop for buttonhole sewing and cutting machines, comprising a member adapted to engage and inoperatively position a cutter-operating member of such a machine, an extensible threadengaging member adj ustably connected with said first named member, and adapted to engage a sewing thread operative in such a machiue,.an l together with said first named member retractable by tension in such thread, and a spring opcratively connected with said first named member and adapted to bc strained by such tension, and by its rcroll. when such tension is diminished, to ause said first named member to move to its engagement position.

3. in automatic cutleustop for buttonrion'me hole sewinfl and cutting machines, comprising a meniber adapted to engage and inoperatively position a cutter-operating member ofsuch a' machine, to engage a sewing thread operative in such a machine, and to be retracted by tension in such thread, a mounting member adapted for mounting said first named member on such a machine, and a spring strained between said first nained and molimting members and adapted to be strainedi'by such tension, and by its recoil, when such tension is diminished, to cause said first named member to move to its engagement position.

4. An automatic cutter-stop for buttonhole sewing and cutting machines, comprising a member adapted to engage and inoperatively position a cutter-operating member of such a machine, to engage a sewing thread. operative in such a machine, and to be retracted by tension in such thread, a mount.

mg member adapted for mounting said first named member on such a machine, a spring strained between said first named and mounting members and adapted to be strained by such tension, and by its recoil, when such tension is diminished, to cause said first named member to move to its engagement position, and a stop on said mounting member adapted to limit the retraction of said first named member.

5. In a device of the character described, the combination of thread tensioning devices, a buttonho'le cutting knife, a cutteradvancing member arranged to operate the cutting knife when shifted, a lever, engaging means on the lever to connect with said out teradvancing member when the lever is swung and prevent movement thereof, an eye member on the lever arranged to engage the sewing thread between said tensioning devices, a spring connected with the lever to shift the lever upon breaking of the thread to cause said engaging means on the lever to engage said cutter-advancing means and ,nevent the operation of the cutter, means for adjusting the tension of said spring, said lever having a series of holes in which said ipring is hooked to permit adjustment of the tension of the spring.

6. In a button hole sewing machine, the combination of thread tensioning devices, a button hole cutter, member arranged to cause the advance of said button hole cutter when shifted, of a slotted mounting bar, a lever pivoted on the bar, a hook on one end of the lever, a pin on said cutter-advancin member arranged to be engaged by said hook when the lever is shifted and thereby to engage the member and' prevent the cutter being: operated, an eye member on the lever and positioned to engage the thread between said tension-devices whereby the lever is thereby normally held with its book out of engagement with and a cutter-advancing.

said pin, and a spring strained between the lever and the slotted bar arranged to swing the lever upon breakage of the thread to cause said engagement of said hook to prevent operation of the cutter.

7. In a button hole sewing machine, the combination with thread tensioning devices, button hole cuttiru means, and a member arranged to cause the advance of the cutter wien shitted, of a slotted bar, a lever pivoted on the bar, a hook on one end of the lever, a pin on said member arranged to be engaged by said hook when the lever is shifted to prevent the operation of the cutter, an eye member on the lever positioned to engage the thread between said tensioning devices whereby the lever is thereby nor mally held with its hook out of engagement with said pin, and a spring connected between the lever and the slotted bar arranged to swing the lever upon breakage of the thread to cause said engagement of sai hook to prevent operation of the cutter, said bar and lover being each provided with-a series oi? holes for adjustment of said spring.

& In a button hole sewing machine, the combination of thread. tensioning devices, button hole cutting means, and a cutter-advancing member arranged to cause the advance of said cutter when shifted, of a slotted mounting bar, a lever pivoted on the bar, a hook on one end of the lever, a pin on said cutter-advancing member arranged to be engaged by said hook when the lever is shifted to prevent the operation of the cutter, an eye member carried by the lever positioned to engage the thread between said tensioning devices whereby the lever isthereby held with its hook out of engagement with said pin, a spring strained between the lever and the slotted bar arranged to swing the lever upon breakage of tire thread to cause engagement of its hook, and a stop on said mounting bar to limit the rctractive movement of the lever.

S). An. automatic cutter-stop for buttonhole sewing and cutting" machines, comprising a mounting bar adapted to be connected with a lixcd part of such machine, a lever pivotally mounted on said mounting bar and adapted to engage and inoperatively position a cutter-operating member of such a machine, to engage a sewing thread operative in such a machine, and to be retracted by ten sion in such thread, and a spring strained between said mounting bar and stop-lever, adapted to be strained by such tension and by its recoil, when such tension is diminished, to cause said lever to move to its engagement position.

10. An automatic cutterstop tor buttonhole sewing and cutting machines, comprising a mounting bar adapted to be connected with a fixed part of such machine, a lever pivotally mounted on said mounting bar, an

,machine and together wit rid. m1

said lever to move to its engagemenuposr.

tion.

,111- An automatic cutterstop for buttonhole sewing and cuttingmachines, comprising a mounting bar adapted to be connected with. a fixed part of such machine, a lever pivotally mounted on said mounting bar, an extensible thread-engaging member adjustably connected with an arm of said lever and adapted to engage a sewing thread in such machine and together with said lever retractable by tension in such thread, the other arm of said lever being adapted to engage and inoperatively position a cutter-operating memher, a spring strained between said mounting bar and lever, adapted to be strained by such tension and by its recoil, when such tension is diminished, to cause said lever to move to its engagement position, and means to varythe resistance of said spring.

12. An automatic cutter-stop for butt0nhole sewing and cutting machines, comprising a member adapted to engage a cutteroperating member of such a machine, to engage a sewing thread operative in such a machine, and to be retracted by tension in such thread, a mounting member adapted for mounting said first named member on such a machine, a spring strained between said. first named and mounting members and adapted to be strained by such mnsion, and by its recoil, when such tension is diminished, to cause said first named member to move to its engagement position, and means for varying the resistance of said. spring.

13. An automatic cutter-stop for button hole sewing and cutting machines, in combi-' nation with two tension devices thereof and comprising a member adapted to engage and inoperatively position a cutter operating member of such a machine, a thread-engaging devlce on sald first named member member, and adapted to be strained by such- .tension' and by its recoil, when said tension is diminished, to cause said. first nanied member to move to its engagement position.

14. An automatic cutter-stop for buttonhole sewing and cut-ting machines, in combination with two tension devices thereof and comprising a member adapted to engage and operatively ber of such a machine, a thread engaging device on said first named member adapted to engage a sewing thread operative in such a machine and together with said first-named member retractable by tension in such thread the retracted position of said thread position a cutter operating memengaging device being to one side of a straight line between said tension devices of such machine, means for shifting said thread engaging device toward one and away from the other of said tension devices, and a spring operatively connected with said first named member, and adapted'to be strained by such tension and by its recoil, when said tension is diminished, to cause said first named member to move to its engagement position.

BERNARD M. KRE'ZL.

l/Vitnesses H. D. PENNEY, JOHN Mounts. 

